<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>写代码啦</title>
    <meta name="viewport" content="width=device-width">
  </head>
  <body>
    <iframe src="" frameborder="0"></iframe>
    <style>

      * {
        margin: 0;
        padding: 0;
      }

      iframe {
        width: 100vw;
        height: 100vh;
      }
    </style>

    <script>
      let search = {}
      location.search.substr(1).split('&').map(s=>s.split('=')).forEach(arr => search[arr[0]] = arr[1])
      let to = decodeURIComponent(search.to)
      let $iframe = document.querySelector('iframe')
      $iframe.src = to
    </script>

  </body>
</html>